package summer_vacation.xuqianlan;

/**
 * Created by lenovo on 2015/9/5.
 */
public class Test_45 {
    public static void main(String[] args) {
        int s=0;
        int n=0;
        for(int i=1;i<=20;i++){
            n=1;
            for(int j=1;j<=i;j++){
                n*=j;
            }
            s+=n;
        }
        System.out.println("1+2!+3!....+20!="+s);
    }




}
